A debugging system used for a data center in a network is disclosed. The system includes a monitoring engine to monitor network traffic by collecting traffic information from a network controller, a modeling engine to model an application signature, an infrastructure signature, and a task signature using a monitored log, a debugging engine to detect a change in the application signature between a working status and a non-working status using a reference log and a problem log, and to validate the change using the task signature, and a providing unit to provide toubleshooting information, wherein an unknown change in the application signature is correlated to a known problem class by considering a dependency to a change in the infrastructure signature. Other methods and systems also are disclosed.